The present invention relates to improvements in apparatus for damping torsion-induced vibrations in the power trains of motor vehicles or the like. More particularly, the invention relates to improvements in apparatus wherein dampers are installed between a plurality of relatively movable flywheels one of which can receive torque from the engine of a motor vehicle and another of which can transmit torque (for example, through the intermediary of a friction clutch) to the input shaft of the change-speed transmission in a motor vehicle.
Apparatus of the above outlined character normally comprise one or more energy storing components which oppose angular movements of the flywheels relative to each other. For example, the energy storing components can include coil springs which are installed in windows of first and second parts one of which is connected with one flywheel and the other of which is connected with another flywheel. When the flywheels are caused or permitted to turn relative to each other, the coil springs store energy which is dissipated as soon as the angular movements of the flywheels are reversed. It is further known to employ dampers in the form of energy storing devices which cooperate with friction or slip linings to bring about a histeresis.
Apparatus of the above outlined character operate properly under certain specific circumstances. They can reduce noise and they can also contribute to the comfort of the occupant or occupants of the vehicle. However, in many instances, the presently known apparatus constitute solutions which are a compromise between an optimum solution and a barely acceptable solution. The reason is that such apparatus must be designed with a view to take into consideration a plurality of often widely different parameters. For example, some of the presently known apparatus can properly reduce noise which is likely to develop in the absence of any dampers between the relatively movable flywheels, or such conventional apparatus can counteract in a reasonably acceptable way those vibrations which develop when the engine is on but the flywheels tend to, or actually do, rotate relative to each other. Attempts to design conventional apparatus with a view to account for a wide variety of operational parameters contribute significantly to the bulk, cost and complexity of such apparatus. For example, the complexity of conventional apparatus will increase if such apparatus are to operate satisfactorily within a wide range of amplitudes of angular displacements of two or more rotary flywheels relative to each other. Still further, such conventional apparatus cannot conform their damping characteristics to all, or even to a reasonably large number of, variable operating conditions. One of the reasons is that the hystereses which develop during different stages of operation of presently used dampers cannot be altered. Moreover, the presently known apparatus are subject to extensive wear and are prone to malfunction.